Electric-arc lamp.



PATENTED JUNE 13, 1905.

R. H. READ.

ELECTRIC ARC LAMP.

APPLICATION FILED 001210, 1902.

HJV NTOR:

\A/ITIQESSESI @c PATENTED JUNE 13, 1905 R. H. READ.

ELEGTRIG ARC LAMP.

APPLICATION FILED OUT. 10, 1902.

2 SHEETS-S11E31 24 FITNESSES! Patented June 13, 1905..

UNITED STATES PATENT OEEIcE.

ROBERT H. READ, OF SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEIV YORK.

ELECTRIC-ARC LAMP.

SPECIFICATION forming part of Letters Patent No. 792,076, dated June 13, 1905.

' Application filed October 10, 1902. Serial No. 126,688.

To all whOm it may concern:

Be it known that I, ROBERT H. READ, acitizen of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in Arc-Lamps, of which the following is a specification.

In using electric-arc lamps on circuits of constant potential it is the common practice IO to connect a considerable dead resistance in series relation to the lamp. As lamps are commonly constructed this is found necessary to steady the are, as without the auxiliary resistance almost the entire drop of electromotive 5 force in the lamp is across the are, creating such a considerable change of voltage under imperfections of the carbons or when a fluctuation at the line-terminal occurs that the arc is suddenly extinguished and the lamp must restart. An absolutely pure carbon permits a smaller external resistance to be employed than when the carbon is not pure or homogeneous; but even omitting every consideration of changes of voltage due to such cause the changes at the line-terminals must be contended with. The employment of a considerable idle resistance ameliorates these interfering conditions by absorbing a considerable portion of the drop across the lampterminals, and thus rendering the voltage fluctuation at the arc of smaller value. The employment of such a resistance, however, is objectionable from an economical standpoint as wasting in heat a considerable amount of energy absorbed by the lamp.

It is the object of this invention to partially dispense with this resistance, so that a smaller resistance maybe employed than has commonly been the case, thereby permitting a larger proportion of the energy consumed by the lamp to be dispensed in the are and increasing the lighting efiiciency.

One of the chief structural features which renders necessary in the usual form of constant-potential lamp the steadying resistance is the sluggish action of the arc-regulating mechanism, due principally to the sluggishness of the regulating-coil, a large current variation being necessary to permit the regulating-cores to change position. I overcome 5 this difiiculty by employing regulating mechanism of peculiar construction.

One feature of my invention involves the employment of an auxiliary quick-acting magnet of short time constant to store energy in a spring when the are is struck, holding the arc-adjusting device under stress, so that a very small range of current variation will permit the spring to respond and shorten the arc. Thus in case the voltage at the arc approaches the danger limit where extinguishment is likely to result the current declines, the magnet of low time constant is weakened, and the strained. spring instantly reacts and shortens the are. This quick-acting auxiliary 5 regulating-magnet may be employed to assist the main regulating-coil in acting upon the positive carbon, or may be independently cmploycd to regulate the negative carbon and may be excited alone by the current or a part 7 0 of the current which passes through the lamp, or excited by a ditferential shunt-current around the are in addition to the series current. With an organization of this kind a lamp may be burned at a much closer point to the line voltage than usual and the economy of its operation considerably enhanced.

The novel features of the invention reside in the employment of a regulating-magnet of short time constant in addition to or in coop- 8O eration with the main regulating-magnet of the lamp.

It comprises also the employment, together with an arc-striking magnet, of a part of relatively small inertia, in which energy is stored 5 when the lamp is burning, ready to quickly respond on a slight decline of current in the lamp.

It comprises also other features of novelty, which will be more particularly hereinafter 9 described, and will be definitely indicated in the claims appended to this specification.

In the accompanying drawings, which illustrate the invention, Figure 1 is a side elevation, partly in section, of an inclosed arclamp embodying my improvements. Fig. 9

Fig. 3

- comprising two spoolsactingon theU-shaped 2the; magnet k1, is to strike thearc. =;fore g1 ven a long range. of. lift, whereas the;

ranges of voltage. spring :9 conduces toward rendering-theauxiliarymagnetquickzacting; but this effect -may be'enhanced by'a special form of;m,ag-

core 2 and connecting. through a clutch 3,with the positive carbon, a dash-pot 5 being connected between the core and the frame. "6'

represents a small'steadying resistance,which' mayiabsorbz from eight to. ten pen cent. ofthe drop across the lamp-terminals. 7represents ,an auxiliary magnet of shortptimeaconstant.

'As-shown ;in .;these .d rawings, this magnet is provided with iron cores anda yoke onz'the lower side, the pole-tips being tapered, as seen, in Fig.2,to cooperatewith .an-armature ,8, mounted so as to have atruevertical move- ;mentagainsta helical spriug..9, a set-screw "and -jam 1 nut being employed {t0 adjust: the tension. of the spring. be sufficient. to cause a quicklift of the lower This; tension should carbon,-wh-ich is.,mounted in apyoke 11, rig- .idly connected, through connecting-rods, with the armatu re. ,thearc is; provided-for gthe .lamp,;these rods maybe worked through lava or other; refractory insulating-bushings mounted in the-globeicover,.as indicated in the drawings. to: prevent tooquick striking of. the are when ,the; lamp circuit is first closed, I prefer to -em-; ;ploy. also; an .additionaledash-pot 5 togoverni .the regulation due to the {additional magnet .VlThere an inclosure around- In order .7. As thus-organizedthe main-functionof' Itis thereregulating-magnet 7 .need have onlyaa short .ShI'Ok6. Small; and quick fluctuations of ,cur-,

vrer 1t,-.whetherdue to hard spots. or irregular;

conducting spots, in thei carbon; or: t05fluctua Mom of line voltage, are compensatedbywhe;

magnet 7, the lifting-magnet 1 being tooslow. to respond to anyexcept very considerable The energy stored in the? net construction, as by giving the lattena vshort core, bylarninating'its core, andby-exciting it by-anumber. of; parallel branches of :the regulating-circuit. Besides this theweight of the parts; which effect, the regulation is less than wheretheheavy arc-striking core must also. be; moved. There. is; therefore .much less mechanical inertia. to be. overcome, inregulastion. form of construction which rendersthe-magmet more quickly. responsive: to. demagnetiza-- Fig. 3 shows this arrangement. Any

tion or which .quickens the response of the :shorteningof, the arcm yibesemployed within-the-l-ines-of-the invention. 'It will be observed that both carbons float freely in obedience' to their magnets, the one straining a spring to insure quick regulation on decline .of-current. .{In Fig. lathe-time constantlof The re-- provements .as appliedito atlamp.inwhichzthe regulation :is i eflected tentirely through i the positiveelectrode. .In this type :1 place between the arc-stril'ring magnet-core. and :the clntchiasectional. core] 212, operating-.within the field of the-auxiliary;regulating-mag- ;net of short timei-constant one member of ithis core, as 112, being secured .ito; a: rod :12, :formingzaafirmattachment'ofwthe core'of the liftingrinagnet, and; theothen being connected togarod .13, moving within-a: tubular part of -.the';r.od and, acting against the helical compression-spring -14.by: means of -.a pin;1-5, .se- 1curefdzto the rod and projecting through slots z16.i n the side of theytube. .The core-sections -1;2;12,are .tapered conically at their confronting. ends-andare slotted, as indicated in Figs. 5; and .7, to. prevent. slnggishness; due; to Foucault. currents ;in ,the. cores. An adjusting- .nu,t i17,=,;co6perating wi,th;,a.- suitable jam-nut, ;is provided to vary: the; tension of the-spring '14. ,A dash pot1'8; is, providedto prevent too ;.sudden striking of :the iarcv due to a.- quick shortening of the, sectional com -and; a dashapot 1.9, as usual; fonthe' lifting-magnet. :It will be: noted thahhere also? both parts. of: themegoverning :systemth at which strikes: theiarc andgthat which regulates it-fioat .in a magnetic; field. On; first closing thev lamp-circuit athe auxiliary-magnet. is firsttov respond; :but :its governing i dash-pot prevents too. sudden separation of the carbons,.-a-nd therefore insures the proper heating of: the carbonrpoints before the arc-is drawn. The slowerliftingmagnet. isthen; acting on its core, and thearc 'ais lengthened )tO its full :limit. Attthe-same time the spring :of I, the auxiliary; magnet has 1' been put under stress, and: the auxiliary mag- -net hasi beena-assisting ;the main 1 liftingrmagneti inseparatingthe carbons. Onza" fluctuation of voltage.inathe.arc,.due tohany" cause, ;the magnet of short ,stime constant :permits -its;core-;to .ilengthenin obedience; to the reac- 1tion.of v.the{control spring and the arc l'iS uickly shortened, an increase of current effected, and a greaterwolatilization: 0ft carbon, and therefore a better condition for the maintenance OflthBniHC, promoted. ltwillibeznoticed that in this organization the advantages of the spring are obtained without an increased effort on the part of the lifting-magnet, and therefore without any detraction from the length of the arc. Control-springs have heretofore been employed in lamps, but mainly in such a way as to operate against the length of the are. In arc-lamps, particularly of the inclosed type, it is desirable to burn the are at as great a length as possible in order to increase the zone of illumination and prevent shadows.

One distinctive feature of the invention is the reduction of the inertia of the arc-adjusting parts without interfering with the freedom of the arc-striking magnet to draw a long are, and 1 wish it understood that this feature may be carried out with other magnetic systems than those shown, any magnetic system which stores energy in a quicklymovable arc-regulating part of the lamp without reducing the arc length falling within its scope. For example. the sectional core might move within the main arc-striking solenoid. Modifications will easily occur to those skilled in the art.

The arc-regulating device can move over the range of arc length and is always ready to respond instantly to small variations of current such as would not effect regulation through the lifting-solenoid except sluggishly. I term this a floating regulator, since the quickregulating device can move over or be floated through the arc length by the lifting-magnet and at any stage of its movement can respond independently oi the lifting effort of the main magnet. In the type shown in Fig. 2 this result is effected by the sectional lifting system and in the type shown in Fig. 5 by the sectional core governing the negative electrode.

hat 1 claim as new, and desire to secure by Letters Patent of the United States, is

1. An electric-arc lamp having a liftingmagnet and armature for the movable carbon, and means responsive to the lamp-current for regulating the arc length, said means being movable independently of the position of the armature and the lifting-magnet.

2. An electric-arc lamp having electrodes relatively movable to strike the are, an arcstriking magnet, a movable element of small inertia to regulate the arc, and means for storing energy during normal operation to act on said element to shorten the are.

3. An electric-arc lamp having an arc-striking magnet, an armature, an electrode governed thereby, and means responsive to minor current variations for regulating the arc length independently of the armature.

4. An electric-arc lamp having a floating are striking and regulating mechanism, the

regulating element being sectional and adapted to store energy when the arc is struck to insure quick response independent of the lifting element when current declines.

5. An electric-arc lamp provided with a lifting-coil and armature having a long range of movement and a short-range regulating-magnet of relatively shorter time constant both acting simultaneously to regulate the are.

6. An electric-arc lamp provided with a lifting-coil and core having a long range of movement, a short-range regulating-magnet of relativel y shorter time constant both acting on the are, and a spring opposing only the shortrange magnet.

7. An electric-arc lamp provided with two operating-magnets, one of long range to strike the arc, and the other of short range and of relatively short time constant to regulate the arc, both magnets acting continuously and simultaneously on the are both responsive to the energy consumed in the lamp.

8. An electric-arc lamp provided with two arc-regulating magnets, one of long range to strike the are, the other of short range to adjust it, both acting simultaneously in response to energy consumed in the lamp, a spring opposing the short-range magnet, and an adjusting device for varying the tension of the spring.

9. A constant-potential electric-arc lamp provided with two arc-regulating magnets, one of long range to strike the arc, the other of short range to adjust it, both acting simultaneously in response to the energy consumed in the lamp, and a small steadying resistance in series with the lamp.

10. An electric-arc lamp provided with two arc-regulating magnets, one of long range and the other of short range both responsive to energy consumed in the lamp, a spring strained by the latter, and a dash-pot acting in conjunction with each magnet.

11. An electric-arc lamp having two areregulating magnets, and a two-part regulating mechanism, said magnets both acting simultaneously and independently of said parts.

12. An electric arc lamp provided with means for striking the are, a sectional carbonlifting mechanism, a spring acting between the sections, means for establishing the arc, and an arc-regulating magnet for putting the spring under stress.

13. An electric arc lamp provided with means for striking the are, a sectional carbonlifting mechanism, a spring acting between the two sections, means for establishing the arc, a regulating-magnet for straining the spring, and a dash-pot for damping the straining movement of the spring.

14. An electric-arc lamp provided with two arc-regulating magnets acting tandem on the same carbon-lifting mechanism, a sectional core in said lifting system controlled by one magnet, a spring governing the core-sections, and a dash-pot for damping the straining movement of the spring.

15. An arc-lamp provided with a long-range magnet, a sectional core between said magnet and the" lamp-clutch, a spring acting between the core parts, and a magnet of short time constant for straining the spring.

16. An arc-lampvprovided witha long-range magnet to strike the are, a sectional core between said magnet and the lamp-clutch, a spring tending to separate the core parts, a I magnet of short time constant responsive to energy consumed in the lamp for straining the spring, and means for damping themovev ments of the clutch.

17.v An arc-lamp provid ed with an are-striking magnet, a regulating-magnet having aseetional core and a spring tending to separate the; core-sections, said core-sections telescoping into one. another.

In witness whereof I have hereunto set my hand this 8th day of October; 1902.

ROBERT H. READ. Witnesses:

BENJAMIN B. HULL, HELEN ORFORD. 

